jdbc.driver = com.mysql.jdbc.Driver
jdbc.url =  jdbc:mysql://localhost:3306/myDatabase
jdbc.username = root
jdbc.password = hwsofts08

代碼

package com.autotesting;

import java.io.IOException;
import java.util.Properties;

public  class Test {
    public static void main(String[] args) {
        Properties properties = new Properties();
        try {
            properties.load(Test.class.getClassLoader().getResourceAsStream("jdbc.properties"));
        } catch (IOException e) {
            e.printStackTrace();
        }
        String url = properties.getProperty("jdbc.url");
        String username = properties.getProperty("jdbc.username");
        String password = properties.getProperty("jdbc.password");
        System.out.println("url is: " + url);
        System.out.println("username is: " + username);
        System.out.println("password is: " + password);
    }
}

執(zhí)行結(jié)果：

連接數(shù)據(jù)庫查詢數(shù)據(jù)

為了連接MySQL數(shù)據(jù)庫，需要先下載mysql-connector-javajar包。

下載地址：

https://mvnrepository.com/artifact/mysql/mysql-connector-java/8.0.30

下載完成后，將mysql-connector-java-8.0.30.jar文件復(fù)制到lib文件夾下，然后右鍵選擇Add as Library

語句

select * from student where sid = 18;

代碼：

package com.autotesting;

import java.io.File;
import java.io.FileInputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Properties;

public  class ConnData {
    public static void main(String[] args) {
        String sql = "select * from student where sid = ?;";
        Properties properties = new Properties();
        try {
            properties.load(new FileInputStream(new File("src/main/resources/jdbc.properties")));
            // 獲取jdbc.properties文件中的數(shù)據(jù)
            String url = properties.getProperty("jdbc.url");
            String username = properties.getProperty("jdbc.username");
            String password = properties.getProperty("jdbc.password");
            // 獲取Connection
            Connection connection = DriverManager.getConnection(url, username, password);
            // 獲取PreparedStatement
            PreparedStatement preparedStatement = connection.prepareStatement(sql);
            // 設(shè)置條件字段值
            preparedStatement.setObject(1, 18);
            // 調(diào)用查詢方法獲取結(jié)果集
            ResultSet resultSet = preparedStatement.executeQuery();
            // 從結(jié)果集獲取查詢數(shù)據(jù)
            while(resultSet.next()){
                String nameValue = resultSet.getObject("sname").toString();
                String genderValue = resultSet.getObject("gender").toString();
                String sidValue = resultSet.getObject("sid").toString();
                System.out.println("sname is "+ nameValue + "; gender is " + genderValue + "; sid is " + sidValue);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

執(zhí)行結(jié)果

-------

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